Focus Detecting Pixel Interpolation Using High-Frequency Component Addition

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Solution Overview

Problem

Existing image processing techniques, such as simple average interpolation, fail to accurately interpolate pixel values when there are outlines or fine line structures near focus detecting pixels, leading to false colors, false structures, and deteriorated image quality.

Innovation Solution

An image processing device that includes a storing unit for focus detecting pixel positions, a pixel interpolating unit, a neighborhood-pixel estimating unit, a high-frequency component calculating unit, and a high frequency component adding unit, which uses spectroscopic characterizations and weight coefficients to calculate precise interpolation pixel values by combining pixel values from neighboring pixels and adjusting for high-frequency components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If simple average interpolation is used to interpolate pixel values at focus detecting pixel positions, then the interpolation process is simple and fast, but when outlines or fine line structures are present in the neighborhood, false colors and false structures occur, and image quality deteriorates

Engineering Contradiction:

Improveinterpolation processing speedVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the interpolation process into multiple stages: first calculating a preliminary interpolation value using simple average, then separately calculating high-frequency components from focus detecting pixel values and neighborhood pixel values, and finally combining them. This segmentation allows the system to maintain speed while improving accuracy by handling different frequency components separately.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different interpolation strategies to different regions. When high-frequency components are detected (indicating outlines or fine line structures), the system enhances the interpolation result locally at focus detecting pixel positions where these structures are present, while maintaining simple average interpolation for uniform regions. This local quality adjustment prevents false colors and structures without slowing down overall processing.

Inventive Principle:

Principle #3Local quality

2Device complexity

If simple average interpolation is used to interpolate pixel values at focus detecting pixel positions, then the calculation process is simple, but structures such as outlines and fine lines are vanished or distorted

Engineering Contradiction:

Improveinterpolation algorithm complexityVSAvoidstructure preservation accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces high-frequency component calculation as an intermediary step between the simple average interpolation and the final result. This intermediary process captures the high-frequency information (outlines and fine lines) that would be lost in simple average interpolation, and then combines it with the low-frequency interpolated values to produce the final accurate result.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8243158B2Image processing device, imaging device, and medium storing image processing program for interpolating at an af pixel position

Publication Date: 2012.08.14 NIKON CORP

AI summary

An image processing device including a storing unit storing the position of a focus detecting pixel of an image-capturing sensor containing plural pixels having spectroscopic characterizations corresponding to respective plural color components with the focus detecting pixel, a pixel interpolating unit generating an interpolation pixel value of the focus detecting pixel by using pixel values of pixels neighboring to the focus detecting pixel, neighborhood-pixel estimating unit calculating an estimation pixel value corresponding to a pixel value when the pixels neighboring to the focus detecting pixel have the same spectroscopic characterization as the focus detecting pixel, a high-frequency component calculating unit calculating a high frequency component of the image by using a pixel value of the focus detecting pixel and the estimation pixel value, and a high frequency component adding unit adding the interpolation pixel value with the high frequency component to calculate a pixel value of the focus detecting pixel.